Melanotan II (MT2) is a synthetic peptide modeled after alpha-melanocyte–stimulating hormone (α-MSH), a naturally occurring hormone involved in skin pigmentation, appetite regulation, and sexual function. MT2 is best known for its ability to stimulate melanin production, leading to skin darkening without the need for prolonged sun exposure.
In addition to pigmentation, MT2 affects several melanocortin receptors, which explains its broader systemic effects.
How Melanotan II Works
MT2 activates melanocortin receptors (MC1R–MC5R) throughout the body. Its primary and most visible effect comes from stimulating MC1R in melanocytes, increasing melanin production in the skin.
Other receptor interactions contribute to:
Appetite suppression
Changes in libido
Modulation of energy balance
Because MT2 acts directly on these receptors, its effects can be noticeable relatively quickly.
Potential Benefits
Reported and studied effects of Melanotan II may include:
Increased skin pigmentation and tanning response
Reduced sensitivity to UV exposure
Appetite suppression
Increased sexual arousal and libido (dose-dependent)
Possible photoprotective effects
Pigmentation effects typically develop gradually and may persist for weeks after discontinuation.
Administration
Commonly administered via subcutaneous injection
The 10 mg designation usually refers to the total amount per vial
Often introduced with low initial dosing and gradually increased
Because of its potency, careful dosing and conservative protocols are emphasized by clinicians and researchers.
Biochemical Characteristics
Peptide Sequence: Nle-Asp(1)-His-D-Phe-Arg-Trp-Lys(1)
Molecular Formula: C50H69N15O9
Molecular Weight: 1024.198 g/mol
PubChem CID: 92432
CAS Number: 121062-08-6
Source: PubChem
MT-2 is typically evaluated as a defined-sequence melanocortin agonist input in receptor binding, signaling, and time-course pathway assays.
Research Applications
In research settings, MT-2 may be used as an experimental input for:
- Receptor pharmacology: comparing potency/efficacy across melanocortin receptor subtypes in cell-based assays.
- Second-messenger signaling: quantifying pathway outputs such as cAMP accumulation and downstream kinase activation (e.g., ERK) under controlled conditions.
- Behavioral neuroscience models: probing melanocortin-linked circuitry in preclinical paradigms studying feeding behavior, reward/impulse-related behavior, and other neurobehavioral endpoints.
- Pigmentation biology: investigating melanocyte-associated signaling and transcriptional programs downstream of melanocortin receptor activation.
- Systems biology / mapping studies: evaluating tissue- or region-specific receptor expression and pathway signatures using agonist-stimulation frameworks.
These applications are presented as examples of laboratory research use and are not medical or clinical claims.
Pathway / Mechanistic Context
MT-2 is discussed as engaging the melanocortin receptor family (MC1R–MC5R), a group of GPCRs that in many experimental systems couple to Gs signaling and drive cAMP generation. In mechanistic workflows, MT-2 is used to map receptor-driven pathway readouts such as cAMP/PKA-linked signaling, ERK phosphorylation, immediate-early gene expression, and downstream transcriptional programs.
Because melanocortin receptors have distinct expression patterns across tissues, MT-2 is often incorporated alongside subtype-selective antagonists, genetic models, or region-specific interventions to support receptor attribution of observed endpoints.
- MC1R: commonly studied in melanocyte and pigmentation signaling models.
- MC3R: investigated in energy-balance and metabolic signaling contexts.
- MC4R: frequently used as a mechanistic anchor in feeding behavior and neurobehavioral pathway studies.
- MC5R: explored in peripheral tissues, supporting tissue-distribution and signaling studies.
Preclinical Research Summary
1. Neurodevelopmental Behavior Models (MIA / ASD-related paradigms)
In a maternal immune activation (MIA) mouse model, MT-2 administration was reported alongside changes in measured autism-like behavioral endpoints and oxytocin-related signaling readouts, supporting continued investigation of melanocortin-linked circuitry in social-behavior paradigms.
Impact of MT-2 on sociability in rats with ASD (MIA) showing that MT-2 returns sociability ratings to near the baseline of control animals (C57).
Source: PubMed
2. Feeding Behavior, Macronutrient Preference, and Satiety Pathways
Human and animal research has examined melanocortin signaling (including MC4R-linked paradigms) for relationships to dietary intake patterns and macronutrient preference. Additional literature discusses leptin–melanocortin network interactions relevant to feeding and energy expenditure regulation.Related work has also examined TRH gene regulation within these broader metabolic circuits.
3. Metabolic Regulation & Glucose-Handling Literature
Metabolic research discusses glucagon as a factor in diabetes pathophysiology and explores CNS-linked signaling contributions to peripheral glucose handling. In hypothalamic-nuclei injection models, melanocortin receptor agonism has been evaluated for effects on glucose uptake endpoints in peripheral tissues, supporting ongoing interest in central regulation of metabolic function.
4. Reward / Impulse-Related Behavioral Research
Rodent studies have reported that melanocortin signaling in regions such as the amygdala may influence alcohol intake behaviors, with MT-2 used as a receptor-agonist probe in these paradigms. Additional work has evaluated combined-intervention designs where MT-2 is assessed alongside naltrexone in binge-like ethanol intake models in mice.
Percent of baseline alcohol consumption in mice treated with naltrexone or naltrexone and MT-2.
Source: PubMed
5. Sexual Behavior Signaling (Clinical and Preclinical Literature)
Clinical research has evaluated MT-2 in the context of psychogenic erectile dysfunction, including a placebo-controlled crossover study reporting effects on erection initiation under the study’s measured conditions.
Note: The studies summarized above describe mechanistic or experimental endpoints in laboratory and preclinical systems and are not intended as medical claims.




Reviews
There are no reviews yet.